1. Technical Field
The present invention relates to a pneumatic tire and, specifically, to a pneumatic tire having a structure in which a carcass ply is wound up from the outside to inside in the direction of width of tire.
2. Background Art
In the related art, pneumatic tires having a structure in which a carcass ply is wound up from the widthwise outer side to inner side of tire, whereby distribution of a tensile force applied to the carcass ply is changed so as to increase a tensile force of a position easy to contribute to tire rigidity, and improve a control stability performance as described in JP-A-2007-131173, JP-A-2002-513360, and JP-A-07-315013 (1995) are known.
JP-A-2007-131173 discloses a pneumatic tire having a structure aiming an improvement of a control stability performance of the tire by having a carcass ply of a single-layer structure and being wound around bead cores from the outside to the inside in the direction of width of tire, arranging ends of the carcass ply inside the bead cores in a radial direction of tire, and winding up the ends of the carcass ply from turn-up positions toward the outside in the radial direction of tire to an extent that the bead cores are not wrapped around.
JP-A-2002-513360 discloses a tire intended to substantially reduce the frequency of occurrence of tire breakage in an early stage with a carcass ply wound up around bead cores from the outside to inside in the direction of width of tire.
JP-A-07-315013(1995) discloses an air radial tire capable of contributing to the weight reduction of the tire and maintenance of tire rigidity without lowering performances such as a control stability or the like by having a configuration that a carcass ply passes through outer surface sides of tire from bead fillers and both ends of the carcass ply are wound up from the outside toward the inside of the bead cores on both sides so as to be supported thereby.
However, since known technologies disclosed in JP-A-2007-131173, JP-A-2002-513360, and JP-A-07-315013 (1995) all have a configuration in which the carcass ply is in direct contact with the bead cores, a tensile force is generated when an inter pressure is applied to the tire, whereby the carcass ply and the bead core are scraped against each other, so that, breakage or deterioration of durability may occur.